Useful for when people want to try some version of the perf tools and don't
wants to download the kernel tarball.

Here is a session using this new target:

  [root@emilia linux-2.6-tip]# make help | grep -i perf
    perf-tar-src-pkg    - Build perf-2.6.35-rc1.tar source tarball
    perf-targz-src-pkg  - Build perf-2.6.35-rc1.tar.gz source tarball
    perf-tarbz2-src-pkg - Build perf-2.6.35-rc1.tar.bz2 source tarball
  [root@emilia linux-2.6-tip]# make perf-tarbz2-src-pkg
    TAR
  [root@emilia linux-2.6-tip]# ls -la perf-2.6.35-rc1.tar.bz2
  -rw-r--r-- 1 root root 295731 May 31 11:18 perf-2.6.35-rc1.tar.bz2
  [root@emilia linux-2.6-tip]# tar xf perf-2.6.35-rc1.tar.bz2
  [root@emilia linux-2.6-tip]# cd perf-2.6.35-rc1
  [root@emilia perf-2.6.35-rc1]# ls
  arch  HEAD  include  lib  tools
  [root@emilia perf-2.6.35-rc1]# cd tools/perf
  [root@emilia perf]# make -j9 2>&1 | tail
      CC arch/x86/util/dwarf-regs.o
      CC util/probe-finder.o
      CC util/newt.o
      CC util/scripting-engines/trace-event-perl.o
      CC scripts/perl/Perf-Trace-Util/Context.o
      CC perf.o
      CC builtin-help.o
      AR libperf.a
      LINK perf
  rm .perf.dev.null
  [root@emilia perf]# ./perf record -a sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.262 MB perf.data (~11457 samples) ]
  [root@emilia perf]# ./perf report | head -12
  # Events: 6K cycles
  #
  # Overhead          Command       Shared Object  Symbol
  # ........  ...............  ..................  ......
  #
       4.73%             perf  [kernel.kallsyms]   [k] format_decode
       4.49%             perf  libc-2.12.so        [.] _IO_file_underflow_internal
       4.38%             init  [kernel.kallsyms]   [k] mwait_idle
       3.29%             perf  [kernel.kallsyms]   [k] vsnprintf
       2.38%             init  [kernel.kallsyms]   [k] sched_clock_local
       2.35%             init  [kernel.kallsyms]   [k] apic_timer_interrupt
       1.86%     sirq-timer/5  [kernel.kallsyms]   [k] find_busiest_group
  [root@emilia perf]#

Acked-by: Michal Marek <mmarek@suse.cz>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20100528185357.GA28009@ghostprotocols.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>